Polymorphism of Leishmaniasis Caused by Leishmania donovani Sensu Lato in Asia

Visceral leishmaniasis (VL), also called kala-azar (KA), is the most severe form of leishmaniasis and often fatal if not treated. The causative species of VL are members of Leishmania donovani sensu law (s.l.), which includes L. donovani, L. infantum, L. archibaldi, and L. chagasi. Its principal victims are children and young adults. Control of KA is urgently needed worldwide. However, due to the diversity of the epidemiological features in each endemic focus, it has not been possible to devise a universal control strategy applicable to all foci. In order to construct a framework of epidemiological, pathological, and taxonomic understanding, and explain how Leishmania species develop different clinical and epidemiological features, further studies on the pathogenesis of different forms of KA and comparative studies of the parasites from different foci are clearly necessary. This chapter summarizes the recent advances in understanding the polymorphism of leishmaniasis as caused by Leishmania donovani s.l. in Asia.